This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-288322, filed Sep. 22, 2000, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a disk drive and, more particularly, to a disk drive that has taken a measure against a shock in dropping and the like.
2. Description of the Related Art
Conventionally, magnetic disk drives (HDDS) as information recording media are prevalently used in information processing apparatuses such as personal computers and the like. When the user inadvertently drops such magnetic disk drive in use, a head or disk in the magnetic disk drive may be damaged or operate erroneously.
To solve this problem, an unstable state of the magnetic disk drive must be detected before any shock acts on the magnetic disk drive to prevent the magnetic disk drive from being damaged. As a technique for implementing this, for example, Jpn. Pat. Appln. KOKAI Publication No. 8-29450 is available.
This document discloses a technique in which a magnetic disk drive has a state sensor that comprises a housing having an internal spherical cavity, a spherical conductive member movably sealed in the cavity, a plurality of electrodes arranged on the inner surface of the cavity, and a plurality of terminals for applying voltages to these electrodes, and data read/write access is interrupted in accordance with the detection state of the state sensor.
However, with the technique of the above document, the state sensor occupies a large area and space in the magnetic disk drive. Also, with the technique of the above document, a change in magnetic disk drive such as dropping or the like can be detected, but it is difficult to accurately determine the current state. Furthermore, with the technique of the above document, operation errors readily occur and the detection precision is low since a mechanism for detecting the state by an analog scheme, i.e., using the conductive member moving inside the cavity is used.
On the other hand, a shock sensor may be used to detect the state by a digital scheme. However, since the shock sensor is dedicated to detect a shock (dynamic acceleration), it cannot detect a change in gravity or tilt (static acceleration).
Accordingly, it is an object of the present invention to provide a disk drive which is capable of precisely detecting an unstable state, dropping state, or the like by a simple arrangement while reducing a mounting area, and is capable of satisfactorily taking a measure against a shock in dropping or the like.
According to one aspect of the present invention, there is provided a disk drive comprising: an acceleration sensor which has at least two detection axes and detects dynamic and static accelerations; an extraction unit which acquires detection signals corresponding to the static acceleration for respective detection axes by extracting frequency components lower than a frequency component associated with the dynamic acceleration; and a processing unit which determines whether or not a head is to be retracted, based on the acquired detection signals for respective detection axes.
According to another aspect of the present invention, there is provided a disk drive comprising: a printed circuit board; an acceleration sensor which is mounted on the printed circuit board, has at least two detection axes, and detects dynamic and static accelerations; an extraction unit which is mounted on the printed circuit board, and acquires detection signals corresponding to the static acceleration for respective detection axes by extracting frequency components lower than a frequency component associated with the dynamic acceleration; and a processing unit which determines whether or not a head is to be retracted, based on the acquired detection signals for respective detection axes.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.